Process of removing foreign matter from used journal box waste oil



1935- w. T. BISSELL El AL 2,023,983

PROCESS OF REMOVING FOREIGN MATTER FROM USED JOURNAL BOX WASTE OIL FiledJuly 20, 1954 4 Wm sh Machine Storage Emma Coogulatinq AqenL Mixing.5Leam Tam v fieming Fl lLer Clean OH Inventofs. v Thomosw DoLDsnWil HamTBiasel I 9m; 1523.. mm

Attormqi atented Dec. 10, 1935 STES NE'E'E PATENT OFFIQE PROCESS 9FREMOVING FOREIGN MATTER FROM USED JOURNAL BOX WASTE OIL Application July20, 1934, Serial No. 736,156

1 Claim.

This invention relates to a method of treating used journal box oil andmore particularly to an oil in which used journal box waste has beenwashed. We are aware of the fact that 5 such oil has been treated in thepast by introducing chemicals so as to set up chemical reactions in thenature of oxidation. Such chemical treatment of the oil is highlyobjectionable for the reason that it is extremely difiicult to eliminateall traces of the chemical even though the oil be thoroughly washedafter treatment. The very fact that the oil must be washed to remove thetreating chemical means that moisture is added to the oil which becomesobjectionable when the treated oil is returned for lubricating purposes.Again any trace of the chemical remaining in the oil when coming incontact with the moisture in the oil will immediately permit thatchemical to again set up some reaction and at times to produce anemulsion.

This used oil, particularly the bath oil which contains the used journalbox oil, has presented a difficult problem to the industry. The oil mustbe renovated in some manner so as to recover the oil to prevent largeloss which would arise if the oil had to be discarded.

This oil, which is the product to be worked upon in our invention, isWell loaded with colloidal matter. Such matter is generally a colloidalsolution of carbonates from coal, dust, and

possibly in some cases, burnt lint; oxides; oleates, principally leadwith some iron, copper, tin, antimony, etc.; and frequently inertsiliceous materials. These materials are so finely comminuted that theyremain suspended in the oil a colloidal state. There is a furthercontamination in the form of lint coming from the waste which remains insuspension in the oil.

The purpose of our invention is to cause a physical separation of thesevarious contaminating materials, particularly all of the materials foundin the oil other than lint, it being desirable, of course, to separatethe lint at the same time the other materials are removed but the lintby'itself causes no serious problem in its removal. Furthermore it isthe object of our invention to cause such separation by a purelyphysical change without any chemical change so that there will be nonecessity at any time for having to wash chemicals out of the oil norwill the danger be present of having some traces of chemical remainingin the oil which would afterwards set up reactions detrimental ineffect.

The type of oil which is herein considered is 5 that which is describedin the U. S. Patent No.

metallic 1,964,326, issued June 26, 1934 to McNamara et al. and also inthe pending U. S. patent application Serial No. 645,222, filed December1, 1932 by McNamara et a1. Further reference is made to the U. S.Patents Nos. 1,783,407, December 2, 5 1930, Conway et al., and1,709,230, April 16, 1929, Potter et al., wherein the same type of oilis encountered.

The invention will now be described in detail with reference being madeto the accompanying 10 drawing wherein the single View is a diagrammaticrepresentation of the process.

The contaminated oil bearing colloidal matter of such type as aboveindicated is for convenience accumulated'in a storage tank 59. Howeverthis 5 tank may be dispensed with in some cases and the dirty oil takendirectly from the Wash machine. In any event the dirty oil is in a drystate substantially free of moisture as it will be when it is taken fromthe wash tank in the process de- 20 scribed in the above indicated U. S.patent application Serial No. 645,222. That is, the oil in the storagetank 10 is free of moisture. A heating and mixing tank II is here shownas being part of the apparatus and is interconnected with the storage 25tank If! by suitable connections whereby oil may be transferred,generally by a pump, from the storage tank to the tank I i. In somecases these two tanks may be combined to be one and the same tank. Wherethe storage tank is employed, 30 the oil in that tank is preferablyheated to reduce the viscosity somewhat, the temperature of the oilbeing raised to around 120 F. or just enough to make the oil easilyhandled. When cold the oil is somewhat viscous and therefore re- 35quires additional Work in handling. As the oil is introduced into thetank ll, sodium silicate is introduced and also a solution of sodiumaluminate. Of course, these agents may be added after the entire volumeor" oil is placed in the 4.0 tank I l but it is easier to mix theseagents with the oil as the oil is flowed therein. Six hundred (600)pounds of about 40 Baum sodium silicate are used for each one thousand(1,000) gallons of dirty oil or in terms of gallons, using the 45 weightof 13.02 pounds per gallon, about fifty (50) gallons of the sodiumsilicate are employed. For the same amount of dirty oil we employ five(5) gallons of a 20% solution in water of the sodium aluminate. silicateand aluminate in combined proportion of from 3 and up of the dirty oil.However, we find no advantage of using over 8% of these agents since thechanges we desire even in the dirtiest oil encountered such as aroundiron In practice we employ the 50.

mines where the ore dust sifts into the journal boxes and contaminatesthe oil and waste therein, an 8% solution will suffice.

After these two agents are introduced into the oil within the tank ll,steam is introduced into the bottom of the tank and allowed to escapetherein to pass up through the oil to agitate it and to heat it.Pressure is allowed to build up in the tank to around fifteen (15)pounds so that the temperature of the oil may be brought up to around240 F. This temperature is maintained for about an hour. The contents ofthe tank ii are then transferred to a settling tank l2 as indicated inthe diagram although where sufficient capacity is available and the oilis not required to be treated in frequent batches, the tank i2 may bedispensed with and the settling operation allowed to take place in thetank H. In either event, the oil is allowed to cool and remainundisturbed for about twelve (12) 'hours although a longer period may beemployed where time is not important. The twelve hour period isindicated since the oil may be allowed to stand over-night. Followingthe settling period, the oil isv pumped from the top of the settlingtank 2 down to the sludge which is found in the bottom of the tank andwhich has settled from the oil. From the settling tank, this top oil isconveyed to a filter l3, preferably of the type as shown and describedin the U. S. Patent No. 1,964.,326.

The sodium silicate and sodium aluminate are employed to producecoagulation without any chemical reaction on the oil or foreign matterin the oil. The agents employed do not oxidize any of the matter andparticularly the organic matter. The purpose of coagulation is to breakdown the colloidal state so as to transform the state from colloidal toa flocculent one so as to release the foreign matter and permit it toprecipitate. This flocculent state is brought about by the sodiumsilicate in the presence of the sodium aluminate. The precipitate at thebottom of the settling tank where the precipitation is allowed to occurundisturbed is found to be a viscous, tarry substance. As thisfiocculent material precipitates, it carries down with it quite a bit ofthe lint in the oil. In fact it has been observed that where theprecipitation is allowed to occur and be carried on undisturbed for anumber of days, the oil above the precipitate is apparently absolutelyfree of lint as well as of the foreign matter.

Metal bases have a stronger affinity for solid articles. Sodium silicateand sodium aluminate both are salts of metal bases and are of a ratherinactive group. Thus these ingredients added to the dirty oil would haveailinity for the solid particles in the oil. A very thorough mixing ofthe ingredients with the oil is essential to get these ingredients intocontact with the comminuted solids entrapped in the oil. Now as the oilmixture is heated, the oil itself tends to become less viscous while thesilicate tends to become more viscous so that the sodium silicate as itthickens will adhere to the solids in the oil and drag those solidsdownwardly through the oil which has had its viscosity lowered by heat.The picture of the process can be likened to an innumerable group ofmagnets tending to pull the solids out of the oil, the magnets being thebase salts which are added, particularly the sodium silicate which hasthe mechanical action of actually thickening to adhere to the foreignparticles in the presence of heat.

The oil pumped or conducted from the settling tank 82 is noticeably freeof foreign matter and is passed through the filter E3 so as to removethe lint. Some of the foreign matter will also be filtered out which hasnot as yet 5 had time to precipitate and the oil, when drawn from thefilter, is then ready for use, having good at least, an analysis as theoriginal lubricating oil.

It is to be particularly noted that in the foregoing process, there isnothing left in the o l taken from the settling tank 32 which requiresthat the oil be washed so that no moisture is introduced in an attemptto free the oil of injurious chemicals. There is no chemical left in theoil since the sodium silicate and sodium aluminate will precipitate andbe found in the sludge in the bottom of the tank I 2. As aboveindicated, where chemicals are employed to bring about chemicalreactions with organic matter in the oils and break down emulsions (theoil herein being considered being free of moisture hence free ofemulsion) must be washed out of the oil by water. Such chemicals may becarried in the oil in the form of 001- loidal salts and therefore aredifficult to remove and then later when the colloidal state is brokendown will attract moisture and then become active to produce damage inthe bearing wherein the oil is to be used.

These chemicals are either highly acid or caustic nature and are used todecompose the foreign matter found in the oil so as to form salts. Suchsalts as formed are soluble only in water and hence water must beemployed to dissolve them and carry them out of that oil. It is repeatedthat in our process, we do not desh'e decomposition but instead merelycause the added ingredients, particularly the sodium silicats to thickenabout the foreign particles so as 4,0 to cause them to precipitate inthe thinned oil.

The precipitate or sludge remaining on the bottom of the settling tankl2 contains some oil since about 70 to 89% of the oil is pumped orconducted from the settling tank above the sludge. After this upper orclear oil has been removed, water is added to the settling tank in avolume equal to that of the sludge and steam is introduced through thesludge to agitate and to bring the sludge and water up to the boilingpoint of Water. After thoroughly agitating, the mass is allowed tosettle for some time so that the oil may float to the top and the sludgesettle. There are then three distinct layers in the tank, oil at thetop, water thereunder, and sludge under the water. The oil is taken fromthe top above the water and the water and sludge drained out of thebottom of the tank and discarded. The oil taken from the top is passedthrough the filter l3 as before indicated. The sludge and water takenfrom the settling tank after the oil has been removed therefrom isinteresting in that when allowed to stand exposed to the atmosphere andthe water allowed to drain or evaporate therefrom, the resultant productwhen dried is a rather hard, gray, substance easily crumbled, and thelint particles are readily observable throughout it.

The fact that the water separates so easily from the oil when the sludgeis treated is ample evidence of the fact that no chemical reaction hastaken place since there are no soaps or emulsions formed when themixture of water and sludge is cooked up by the introduced steam. Thedried sludge is absolutely free from any traces of oil and the wateritself is clearly separated from the oil.

The only reason for adding the water to the sludge. is to bring about amechanical separation of the oil from sludge so as to float the oilthereout.

While we have herein described our invention in one particular form, itis obvious that deviations in the several steps outlined and in theapparatus employed may be had without departing from the spirit of theinvention, and we, therefore, do not desire to be limited to thatprecise form beyond the limitations as may be imposed by the followingclaim.

We claim:

That process of removing finely divided suspended foreign matter fromused journal box waste oil, which consists of adding about 600 pounds ofsodium silicate and about five gallons of a 20 per cent water solutionof sodium aluminate to about one thousand gallons of dirty oil, thecombined proportion of the silicate and aluminate ranging from 3 to 8per cent of the oil, agitating and heating the oil and chemical mixtureto above 212 F., and then allowing a precipitate to form.

WILLIAM T. BISSELL. THOMAS W. POTTER.

